• Posted January 23, 2025

Why Sparkling Water May (Or May Not) Help You Lose Weight

THURSDAY, Jan. 23, 2025 (HealthDay News) — Chalk up a partial win for health influencers who tout the slimming benefits of sparkling waters.

New research out of Japan affirms that carbonated water may, indeed, promote weight loss by lowering blood sugar levels, allowing cells to burn fat between meals for energy more efficiently.

But don't buy a smaller wardrobe just yet. The findings suggest that any benefit is small. 

Blood sugar levels dropped only temporarily, and study author Dr. Akira Takahashi said the carbonated water would have only a small impact on calorie consumption.

"Carbonated water is not a standalone solution for weight loss," he wrote in the study, which was published Jan. 20 in the journal BMJ Nutrition, Prevention & Health.

Seltzers and sparkling or carbonated waters have gained a following among health buffs for their purported effects on body mass. 

Some point to a small 2017 study that found carbonated drinks stimulated appetite by increasing levels of the hunger hormone, ghrelin. But findings of that study, which involved only 20 people and male rats, have never been replicated.

Takahashi's new research, expands on a 2004 investigation of hemodialysis by his team at Tesseikai Neurosurgical Hospital in Shijonawate, Japan. He is a physician in the hospital's kidney dialysis center.

Hemodialysis is a process that occurs during kidney dialysis, when CO2 enters the blood, just as it would when carbonated water is consumed, CNN noted. 

The 2004 study showed that blood sugar (glucose) levels dropped when CO2 is added to blood, but the new research concluded that the amount of glucose burned would not be enough for significant weight loss.

"When carbonated water is consumed, CO2 is absorbed into the blood vessels in the stomach," Takahashi told told CNN in an email.

But, he added in the email, "a balanced diet and regular exercise remain essential for effective weight management."

Keith Frayn, a professor emeritus of human metabolism at the University of Oxford in the U.K. who reviewed the findings, told CNN that red blood cells cannot fully "burn" the glucose. As such, it will be recycled by the liver.

"If fizzy drinks were to be shown to lead weight loss, it would be much more likely through effects of feelings of fullness," he said.

A registered dietitian with University of Chicago Medicine said sparkling water may, indeed, have a place in weight management.

Bubbly water can make a person feel fuller, helping dieters who find it hard to resist hunger pangs, said Lori Welstead, who was not involved in the study.

"We have some people for whom these sparkling or tonic waters can create fullness, and others for whom it helps with digestion," she told CNN.

But, she warned, more than one or two fizzy waters a day could have any unintended side effect.

"If someone's coming in and they're saying, 'Oh my gosh, I'm gassy, I'm bloated, I'm burping, I'm feeling so sick all day,' it could be due to drinking fine cans of carbonated water each day," Welstead said, adding: Don't overdo it.

More information

There's more about the health benefits -- and potential harms -- of carbonated water at UChicago Medicine.

SOURCE: BMJ Nutrition, Prevention & Health, Jan. 20, 2025; CNN